The invention relates to an apparatus and method for automatically folding down back seats in a motor vehicle, as generically defined by the independent claims.
In many motor vehicles, particularly in dual purpose vehicles that are distinguished by a large, flat loading surface, the cargo space or cargo volume can be increased by folding down the back seats. This folding down is often quite difficult, because it is usually only possible from the rear doors of the vehicle. With a split rear bench seat, each of the seat parts must also be folded down from the respective side of the vehicle. In addition, more often than not, locking mechanisms have to be actuated or seatbacks or seat bottoms have to be moved from a xe2x80x9clocked positionxe2x80x9d with an increased expenditure of force.
For these reasons, the folding down of back seats is generally time consuming and stressful. It is therefore desirable to automate the folding down of back seats for the purpose of enlarging the cargo volume through the use of adjusting drive mechanisms of the type that are already commonly used to adjust front seats.
The device according to the invention, with the features of the main claim, has the advantage that folding down the back seats in order to enlarge the cargo volume in a vehicle is made significantly easier because this no longer has to be carried out by hand, but can occur automatically at the press of a button. In order to adjust the different seat elements, a first drive mechanism is provided at a rotation point of a seat bottom, a second drive mechanism is provided at a slide point of a headrest, and a third drive mechanism is provided at a rotation point of a backrest. The disposition of these drive mechanisms permits the automatic folding and achieves a flat, self-contained, enlarged cargo space.
It is advantageous if the seat elements, which constitute a part of the loading surface, are formed or embodied so that they integrate into the cargo space as well as possible and are able to withstand the increased stresses which a cargo space is subjected to.
Advantageous improvements of the apparatus according to the main claim are possible through the measures taken in the dependent claims.
If sensors are provided which detect the position of the moving seat elements, then it is clear where the individual seat elements are positioned at any time. This is advantageous because this information can be used for control purposes. Potentiometers are sensors that are suitable for this and are respectively embodied as rotary potentiometers at the respective rotation points and are embodied as sliding potentiometers at the sliding points. A continuous detection of the position of the seat elements over the entire movement range is assured with these known sensors.
In exactly the same manner, magnetic or optical sensors can be used, by means of which the position of the seat elements can be determined by detecting the speed of the drive mechanism. Particularly suitable candidates for these magnetic sensors turn out to be Hall sensors that are attached to a drive shaft of a motor and detect its position, speed, and rotation direction.
It is also conceivable that the sensors are accommodated in a control unit and detect a signal, which is typical for the position of the seat elements and which comes from the drive mechanisms. For example, a signal of this kind is the current waviness produced by means of a commutator of the motor.
In addition, a control unit is advantageous which remains in contact with both the drive mechanisms and the sensors for position detection. This control unit can not only cause the drive mechanisms to move the seat elements, it can also influence the drive mechanisms in reaction to impulses of the sensors. Consequently, the decisive advantage is achieved that the system is in a position to detect incorrect movements and if need be, to correct them.
For example, if the seat bottom is folding upward so slowly that a collision with the downward-folding seatback is imminent, then the control unit can detect this based on the position data and can influence the drive mechanisms in such a way that the folding down of the seat back occurs more slowly or is stopped temporarily.
If a correction of the movements is not possible because certain seat elements cannot be moved by the desired amount, for example due objects being disposed on them, then the entire process can be stopped or reversed in time before more serious damage occurs.
In order to actuate the apparatus, an operating element is provided, which communicates with the control unit and initiates the movement of the seat elements. With this operating element, the corresponding commands for folding the back seats down or raising them into the upright position can be transmitted to the control unit. In this connection, it is advantageous if this operating element is disposed in the vicinity of the trunk lid or the hatch because the fold-down mechanism is needed particularly when loading or unloading the vehicle.
A corresponding method for folding down back seats in a vehicle for the purpose of enlarging the cargo volume can be carried out with the apparatus according to the invention disclosed in the main claim. With this method, a controlled movement of the individual seat elements of the back seat takes place, wherein when the back seat is folded down, first a seat bottom is raised upright, then a headrest is retracted, and finally, a seatback is folded down. Naturally this sequence is not absolutely required; it is only important that it produces the desired results. The sequential process is even less absolutely necessary; on the contrary, it is quite advantageous if the movements of the seat elements occur at the same time. This leads to a considerable reduction in the adjusting time.
If the current position of each of the moving seat elements is detected via sensors and these data are transmitted to a control unit, then it is possible that the control unit exerts a corrective influence on the drive mechanisms. This has the previously mentioned advantage that an imminent incorrect adjustment of the simultaneously moving seat elements is detected and can be corrected or stopped by means of the drive mechanisms.
The corrective influence, however, can also be effected in the event that objects become clamped in the seat, wherein this can be detected, for example, by evaluating speed changes.
With the method, the provision is also made that the movements of the seat elements can be reversed. This is sensible and advantageous because the reverse process of moving the back seat into the upright position again manually is just as difficult as folding the back seats down. The movements then occur in the reverse sequence, or in the case of simultaneous movement, occur in accordance with the sequence provided for this and predetermined by the control unit. The reversal of the movement procedure can be achieved without additional expense.